Omega Engineering OMG-CONV-485-ISO manual Technical Description

Technical Description

Technical Description

The OMG-CONV-485-ISOconverts an existing RS-232 serial port into a field selectable RS-422/485 port for industrial automation and control applications.

Connector Pin Assignments

RS-232 Signals (DB-25 Female)

Signal	Name	Pin #	Mode
GND	Ground	7
RD	Receive Data	3	Input
CTS	Clear To Send	5	Input
DSR	Data Set Ready	6	Input
DCD	Data Carrier. Detect	8	Input
RI	Ring Indicator	22	Input
TD	Transmit Data	2	Output
RTS	Request to Send	4	Output
DTR	Data Terminal Ready	20	Output

Note: These assignments meet EIA/TIA/ANSI-232E DTE

Technical Note: The modem control signals are biased in the following fashion: RTS and CTS are connected, DTR is connected to DCD and DSR, and RI is tied inactive.

RS-422/485 Pin Assignments (6 Position Screw Terminal)

Signal		Name	Pin #	Mode
RDB	RX+	Receive Data Positive	1	Input
RDA	RX-	Receive Data Negative	2	Input
TDB	TX+	Transmit Data Positive	3	Output
TDA	TX-	Transmit Data Negative	4	Output
GND	GND	Ground	5
SHIELD	SH	Shield	6

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